To get only numeric values

To  retrieve only numeric values from both numeric& character value

In 10 g

Select  regexp_replace(regexp_replace('5RTYDDB','([[:punct:]])'),'([[:alpha:]])')
  from dual t 
 
In 9i  
 
 select replace('BBd3',TRANSLATE('BBd3', ' +-.0123456789', ' '),'') from dual

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